Barrier Fabrics

ABSTRACT

A process for manufacturing a nonwoven barrier fabric having a first face and an second opposite face, with the steps of applying a primer composition by vapor or aerosol deposition, to the first face of the fabric to form a layer of the primer composition, wherein the primer composition is essentially free of fluorinated compound, and applying a barrier composition comprising at least one unsaturated fluorinated compound by vapor or aerosol deposition to the layer of primer composition to form at least one, and preferably from one (1) to four (4), more preferably two (2) or three (2), layers of the barrier composition on the layer of primer composition and a fabric obtainable according to the process.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of barrier fabrics and the manufacture thereof.

2. Description of the Related Art

Nonwoven fabrics are versatile materials that may be used in multiple applications such as for example garment applications, medical applications, personal protection applications, filtering applications and much more.

As such, the functional requirements for nonwoven fabrics can vary considerably, depending on the intended use or application.

For instance, garments made of nonwoven fabrics may be required to have multiple properties, such as for example antistatic and alcohol repellent properties, whereas other types of garments may need a built-in disinfecting property. In order to confer the multiple properties, the nonwoven fabrics are generally treated with one or more suitable chemical agents such as antistatic agents, repellent agents and others.

However, combining multiple properties in a nonwoven fabric is not void of complications, since most of the chemical agents conferring distinct properties are incompatible with each other and cannot be combined without negatively affecting each other.

Therefore, even if mutually detrimental agents are applied on the opposing sides of a fabric, the agents can migrate through the fabric and cancel out each other's properties in the worst case. This problem is further exacerbated when the fabrics are very thin, low basis weight, and/or very porous.

For this reason, different methods have been proposed in the technical field of nonwoven fabrics which allow for the combination of conflicting chemical agents on a nonwoven fabric.

WO2009/077889 describes a nonwoven web having improved antistatic properties and alcohol repellency, in which the nonwoven web is manufactured using a mixture of an antistatic agent and a thermoplastic polymer, i.e. the antistatic agent is spun into the nonwoven web. Spinning the antistatic agent into the nonwoven web negates its detrimental effect on the alcohol repellant agent which can then be applied by vapor deposition. However, spinning in an antistatic agent into the nonwoven web requires multiple, time consuming adjustments to the manufacturing process.

WO2006/055842 describes a method of finishing a barrier fabric by applying a non-aqueous solution of low surface tension solvent and a fluorochemical, removing the solvent, and applying an aqueous-based antistat to a surface of the barrier fabric.

Furthermore, the barrier compositions applied to most nonwoven barrier fabrics comprise extensive amounts of expensive fluorinated compounds, which represent a considerable part of the manufacturing cost. While the barrier effect of a fabric generally increases with the amount of fluorinated compounds applied thereon, there is always a desire to reduce the content of such expensive compounds while nonetheless keeping sufficient barrier properties.

Thus, there is a strongly felt need to provide a fabric in which multiple properties conferred by potentially, mutually detrimental chemical agents can be easily combined, preferably at low concentrations, even in thin and porous fabrics, as well as a process for manufacturing such fabric.

SUMMARY OF THE INVENTION

The present invention provides for a process for manufacturing a nonwoven barrier fabric having a first face and an second opposite face, comprising the steps of

-   (a) applying a primer composition, by vapor or aerosol deposition,     to the first face of the fabric to form a layer of said primer     composition on the first face of the fabric, wherein the primer     composition is essentially free of fluorinated compound, and -   (b) applying a barrier composition comprising at least one     unsaturated fluorinated compound, by vapor or aerosol deposition, to     the layer of primer composition to form at least one, and preferably     from one (1) to four (4), more preferably two (2) or three (2),     layers of said barrier composition on the layer of primer     composition.

Furthermore, the present invention provides for a fabric obtainable according to the above process.

DETAILED DESCRIPTION OF THE INVENTION

The features and advantages of the present disclosure will be more readily understood, by those of ordinary skill in the art, from reading the following detailed description.

It is to be appreciated that certain features of the disclosure, which are, for clarity, described above and below in the context of separate embodiments, may also be provided in combination in a single embodiment.

Conversely, various features of the disclosure that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any sub-combination. In addition, references in the singular may also include the plural (for example, “a” and “an” may refer to one, or one or more) unless the context specifically states otherwise.

The term “fiber” as used herein refers to staple fibers, stretch-broken fibers as well as continuous filaments, both natural and/or synthetic.

The term “nonwoven fabric” as used herein refers to any fabric comprising a structure of individual fibers that are positioned in a random manner to form a planar material without an identifiable pattern, as opposed to a knitted or woven fabric. Non-limiting examples of nonwoven fabrics are meltblown fabrics, spunbond nonwoven webs, staple-based fabrics including carded and air-laid fabrics, spunlaced fabrics, flashspun fabrics such as the fabrics commercially available from E. I. du Pont de Nemours and Company, Wilmington, Del. (DuPont) under the trademark Tyvek®, as well as any combinations of the above.

The term “woven fabric” as used herein refers to a fabric having at least one weft and at least one warp that are positioned in an periodic manner to form a planar material with an identifiable pattern, as opposed to nonwoven fabric.

The term “(meth)acrylic” as used herein refers to both acrylic and methacrylic .

The term “fluoro(di)acrylate” as used herein refers to both fluoroacrylate and fluorodiacrylate.

The term “hydrostatic head” as used herein refers to the resistance to water penetration, as measured according standard EN 20811, in centimeters.

The term “MVTR” refers to the moisture vapour transition rate as measured according to EN ISO 12572 (climate C with the wet-cup method).

The term “trace amount” refers to less than 1000 ppm.

The terms “areal density” and “areal weight” are used interchangeably, and are used herein to refer to the weight of a fabric per unit area.

The present invention provides for a process for manufacturing a nonwoven barrier fabric having a first face and an second opposite face, comprising the steps of applying a primer composition, by vapor or aerosol deposition, to the first face of the fabric to form a layer of said primer composition on the first face of the fabric, wherein the primer composition is essentially free of fluorinated compound, and applying a barrier composition comprising at least one unsaturated fluorinated compound, by vapor or aerosol deposition, to the layer of primer composition to form at least one, and preferably from one (1) to four (4), more preferably two (2) or three (3), layers of said barrier composition on the layer of primer composition.

Because the primer layer is applied by vapor or aerosol deposition, the primer composition of the primer layer is essentially only present on the first face of the nonwoven barrier fabric and does not extend into the pores, or interior interstices, of the fabric, as would be the case when other, unsuitable deposition methods are used. Stated alternatively, the interior of the nonwoven barrier fabric is essentially free of primer and barrier composition.

Exemplary deposition methods that are unsuitable for applying the primer and barrier compositions in the process of the present invention are knife coating, roll coating, screen printing, kiss roll coating, dipping, soaking, and others.

According to the process of the invention, suitable nonwoven barrier fabrics may be chosen among such comprising one or more natural, or synthetic (man-made) fibers or filaments.

In the case where the nonwoven barrier fabric comprises one or more natural fibers or filaments, these can be chosen among cellulose, cotton, wool, silk, sisal, linen, flax, jute, kenaf, hemp, coconut, wheat, rice, and/or mixtures thereof.

In the case where the nonwoven barrier fabric comprises one or more synthetic (man-made) fibers or filaments, these can be chosen among polyamides, polyesters, polyimide, polyolefins, and/or and mixtures thereof,

Preferably, the nonwoven barrier fabric can be chosen among polyolefinic or polyester nonwoven fabrics, or mixed polyolefinic/polyester nonwoven fabrics.

Polyolefinic nonwoven fabrics can preferably be chosen among polyethylene nonwoven fabrics, polypropylene nonwoven fabrics or mixed polyethylene/polypropylene nonwoven fabrics.

Polyester nonwoven fabrics can preferably be chosen among poly ethylene terephthalate (PET) nonwoven fabrics, polyhydroxylalkanoate nonwoven fabrics (PHA) such as for example polylactic acid (PLA), or mixed PET/PHA nonwoven fabrics.

Most preferably, the nonwoven barrier fabric in the process according to the invention is a polyethylene flash-spun fabric.

The nonwoven barrier fabric in the process according to the present invention has a areal density of from 5 g/m² to 500 g/m², or even from 10 g/m² to 250 g/m² or even from 30 g/m² to 90 g/m².

The nonwoven barrier fabric in the process according to the invention may be a combination of two or more individual layers of nonwoven fabric. It may be, for example, a laminate combining two or more different types of woven or nonwoven fabrics, such as for example a laminate of at least one polyethylene nonwoven fabric and at least one polypropylene nonwoven fabric. Laminates of two or more different types of nonwoven fabrics known in the art are SMS laminates, also called Spunbond-Meltblown-Spunbond laminates.

The process according to the present invention comprises the steps of applying, preferably by vapor or aerosol deposition, a primer composition to the first face of the nonwoven barrier fabric to form a layer of said primer composition on the first face of the fabric, wherein the primer composition is essentially free of fluorinated compound. Stated alternatively, the primer composition comprises only trace amounts of fluorinated compound.

The primer composition on the first face of the fabric may be any composition suitable for conferring a priming functionality, and optionally one or more additional functionalities, and may be applied in amounts of from 0.2 to 2 grams per square meter and preferably of from 0.4 to 0.8 grams per square meter.

The primer composition is essentially free of fluorinated compounds and preferably also essentially free of silicon compounds, and preferably comprises at least one crosslinkable monomeric compound, having at least one olefinically unsaturated group, such as for example (meth)acrylic acid or (meth)acrylic acid esters like 1,3-butylene glycol dimethacrylate; 1,4-butanediol dimethacrylate; 1,6 hexanediol diacrylate (HDDA);1,6 hexanediol dimethacrylate (HDDMA), alkoxylated diacrylate; diethylene glycol dimethacrylate; dipropylene glycol diacrylate; dipropylene glycol diacrylate; ethoxylated (10) bisphenol A diacrylate; ethoxylated (2) bisphenol A dimethacrylate; ethoxylated (3) bisphenol A diacrylate, ethoxylated (3) bisphenol A dimethacrylate; ethoxylated (4) bisphenol A diacrylate; ethoxylated (4) bisphenol A dimethacrylate; ethoxylated bisphenol A dimethacrylate; ethoxylated bisphenol A dimethacrylate; ethoxylated(10) bisphenol A dimethacrylate; ethylene glycol dimethacrylate; ethylene glycol dimethacrylate; polyethylene glycol (200) diacrylate; polyethylene glycol (400) diacrylate; polyethylene glycol (400) dimethacrylate; polyethylene glycol (600) diacrylate; polyethylene glycol (600) dimethacrylate; 1.10-bis(acryloyloxy)decane; polyethylene glycol (400) diacrylate; polyethylene glycol dimethacrylate; propoxylated (2) neopentyl glycol diacrylate; propoxylated neopentyl glycol diacrylate; tetraethylene glycol diacrylate; tetraethylene glycol dimethacrylate; tricyclodecane dimethanol diacrylate; tricyclodecanedimethanol dimethacrylate; triethylene glycol diacrylate; triethylene glycol dimethacrylate; tripropylene glycol diacrylate; 1.10-bis(acryloyloxy)decane and/or combinations thereof.

Most preferably, the at least one crosslinkable monomeric compound having at least one olefinically unsaturated group may be a propoxylated neopentyl glycol diacrylate, a 1.10-bis(acryloyloxy)alkane such as 1.10-bis(acryloyloxy)decane, or mixtures thereof.

The process according to the present invention further comprises the step of applying, preferably by vapor or aerosol deposition, a barrier composition comprising at least one unsaturated fluorinated compound, to the layer of primer composition to form at least one, and preferably of from one to four, more preferably two or three, layers of said barrier composition on the layer of primer composition.

The barrier composition may be any composition comprising at least one unsaturated fluorinated compound and suitable for conferring barrier functionality.

The amount of barrier composition per layer of barrier composition may be of from 0.1 to 1 grams per square meter, and more preferably of from 0.4 to 0.8 grams per square meter. For example, in the case where two layers of barrier composition are applied, the overall quantity of applied barrier composition corresponds to a twofold of the above-mentioned amount, i.e. of from 0.2 to 2 grams, more preferably of from 0.8 to 1.6 grams per square meter.

It has been found that the barrier properties of a fabric that can be obtained by applying a fixed amount of barrier composition onto said fabric can be surprisingly increased by applying said fixed amount of barrier composition in more than one layer. For example, the barrier properties, or repellency rating, of a fabric coated with one layer of barrier composition in an amount of 1.2 grams per square meter are surprisingly inferior to the same fabric coated with the same absolute amount of barrier composition, but where the amount of barrier composition is divided among two layers of 0.6 grams per square meter each. Stated otherwise, for a given coating weight it is preferable to have a higher number of layers in order to get improved repellency.

Preferably, the barrier composition further comprises of from 10 to 50 weight percent or of from 10 to 35 weight percent of the at least one crosslinkable monomeric compound as defined above for the primer compositions, the weight percent being based on the total weight of the barrier composition. More preferably, the at least one crosslinkable monomeric compound comprised in the barrier layer is chosen from a propoxylated neopentyl glycol diacrylate, a 1.10-bis(acryloyloxy)alkane such as 1.10-bis(acryloyloxy)decane, or mixtures thereof.

In a preferred embodiment, the process according to the present invention provides for manufacturing a nonwoven barrier fabric having a first face and an second opposite face, comprising the steps of applying a primer composition, preferably by vapor or aerosol deposition, to the first face of the fabric to form a layer of said primer composition on the first face of the fabric, wherein the primer composition is essentially free of fluorinated compound, and applying a barrier composition comprising at least one unsaturated fluorinated compound, by vapor or aerosol deposition, to the layer of primer composition to form of from one (1) to four (4), and more preferably two (2) or three (3), layers of said barrier composition on the layer of primer composition.

The unsaturated fluorinated compounds useful in the present process may be chosen from compounds comprising at least one unsaturated fluorinated monomer, such as for example perfluoroalk(di)enes having the general structure of

(CH₂═CH₂)_(z)(C_(n)F_(2n+2−z)),

wherein z is an integer ranging of from 1 (when the unsaturated fluorinated monomer is a perfluoroalkene) to 2 (when the unsaturated fluorinated monomer is a perfluoroalkdiene) and n is an integer ranging from 1 to 14, specific examples being 3,3,4,4,5,5,6,6,7,7-decafluoro-nona-1,8-diene; 3,3,4,4,5,5,6,6,6-nonafluoro-hex-1-ene; or such as for example fluoro(di)acrylate monomers having the general structure of

[CH₂═CRCOO(CH₂)_(x)(Su)_(y)]_(z)(C_(n)F_(2n+2−z)),

wherein n is an integer ranging from 1 to 14, x is an integer independently ranging from 1 to 8, R is independently a hydrogen atom or an alkyl group with a chain length varying from 1 to 16 carbons and is preferably a methyl or ethyl group, Su is a sulfonamide group, y is an integer independently ranging from 0 to 1, and z is an integer ranging of from 1 to 2. In many instances, the unsaturated fluorinated compound may be comprised of a mixture of fluoro(di)acrylate monomer homologues corresponding to different independent values of n,y, z and x.

Specific examples of such fluoro(di)acrylate monomers are acrylic acid 2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctyl ester; acrylic acid 2-methyl-2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctol ester; acrylic acid pentafluoroethyl ester; acrylic acid 2-methyl-pentafluorophenyl ester; 2,3,4,5,6-Pentafluorostyrene; acrylic acid 2,2,2-trifluoroethyl ester; acrylic acid 2-methyl-2,2,2-trifluoroethyl ester; 2, 2, 3, 3, 4, 4, 5, 5-octafluoro-1,6, hexanediol diacrylate and 1,1,5,5-tetrahydroperfluoro-1,5-pentanediol dimethacrylate.

Fluoro(di)acrylate monomers of the aforementioned type can be commercially obtained from DuPont under the trademark ZONYL® or CAPSTONE.

Unsaturated silicone compounds may comprise at least one silicone (di)acrylate monomer having the general structure of;

[CH₂═CRCOO(CH₂)_(x)]_(z)(SiR₂[SiR₂O]_(n)OSiR_(4−z))

wherein n is an integer independently ranging from 1 to 50, x is an integer independently ranging from 1 to 8, R is independently an hydrogen atom or an alkyl group with a chain length varying from 1 to 16 carbons and is preferably a methyl or ethyl group, z is an integer ranging from 1 (when the silicone compound is an acrylate) to 2 (when the silicone compound is a diacrylate). In many instances, the silicone compound may be comprised of a mixture of silicone (di)acrylate monomer homologues corresponding to different values of n, z and x.

Preferably, the hydrophobic agent is chosen among the unsaturated fluorinated compounds, and more preferably among fluoro(di)acrylate monomers.

The primer and barrier compositions forming the respective primer and barrier layers may optionally comprise anti-microbial compositions, thermally reflective compositions, flame retardant compositions, ink receiving compositions, dyeing compositions, thickening compositions, adhesion promoter compositions, UV absorbing compositions, optical brightener compositions, and/or combinations thereof.

In the process of the present invention, the primer composition forming the layer of primer composition on the first face of the nonwoven barrier fabric may be applied by vapor or aerosol deposition.

The application of the primer composition by vapor deposition can be achieved by evaporating the primer composition in a vacuum and condensing it on the first face of the fabric to form a layer of primer composition and subsequently curing the formed layer of primer composition. An exemplary vapor deposition method is described in European patent 1618225 to Sigma Laboratories of Arizona, Inc. Alternatively, the application of the primer composition by aerosol deposition can be achieved by creating an aerosol of primer composition at atmospheric pressure in a process gas, exposing the aerosol to a suitable ionizing plasma discharge and orienting the aerosol onto the fabric in a process known as “atmospheric pressure plasma liquid deposition” (APPLD).

Because only the surface fibers or filaments of the first face of the nonwoven barrier fabric are coated with the primer composition in both vapor deposition and aerosol deposition, the breathability of the fabric is not negatively affected, i.e. the breathability is maintained.

In the case where the primer composition is applied by vapor deposition, the thus formed layer of primer composition is cured immediately after condensing on the first face of the fabric by exposing it to high energy radiation such as for example visible light, infrared radiation (heat), ultraviolet radiation and/or ionizing radiation such as gamma rays, X-rays or electron beam.

In the case where the primer composition is applied by aerosol deposition, and in particular atmospheric pressure plasma liquid deposition (APPLD), the curing step comprises the steps of exposing the primer composition aerosol to a suitable plasma discharge in which the ionized process gas molecules generate free radicals on the surface of the aerosol droplets, and the step of orienting the aerosol onto the fabric where the aerosol droplet surfaces react with the fabric upon mutual contact. Representative examples of an apparatus used to generate such a plasma discharge include those provided by WO2001/59809, WO2002/28548, WO2005/110626, US2005/0178330.

Before applying the primer composition to the first face of the fabric, the first face of the fabric can preferably have a high energy treatment applied thereon, such as for example, a plasma etching, plasma treatment, corona discharge treatment or an electrostatic discharge treatment.

In the process of the present invention, the barrier composition forming of from one to four layers of barrier composition on the layer of primer composition of the nonwoven barrier fabric is applied by vapor or aerosol deposition.

The application of the barrier composition by vapor deposition can be achieved by evaporating the barrier composition in a vacuum and condensing it on the layer of primer composition of the fabric to form of from one to four layers of barrier composition and subsequently curing the formed layer(s) of barrier composition. An exemplary vapor deposition method is described in European patent 1618225 to Sigma Laboratories of Arizona, Inc.

Alternatively, the application of the barrier composition by aerosol deposition can be achieved by creating an aerosol of barrier composition at atmospheric pressure in a process gas, exposing the aerosol to a suitable ionizing plasma discharge and orienting the aerosol onto the layer of primer composition of the fabric in a process known as “atmospheric pressure plasma liquid deposition (APPLD)”.

Because only the surface fibers or filaments of the first face of the nonwoven barrier fabric are coated with the primer composition in both vapor deposition and aerosol deposition, the breathability of the fabric is not negatively affected when additional layer(s) of barrier composition are applied on top of the layer of primer composition.

In the case where the barrier composition is applied by vapor deposition, the thus formed layer of barrier composition is cured immediately after condensing on the layer of primer composition of the fabric by exposing it to high energy radiation such as for example visible light, infrared radiation (heat), ultraviolet radiation and/or ionizing radiation such as gamma rays, X-rays or electron beam.

In the case where the barrier composition is applied by aerosol deposition, and in particular atmospheric pressure plasma liquid deposition (APPLD), the curing step comprises the steps of exposing the barrier composition aerosol to a suitable plasma discharge in which the ionized process gas molecules generate free radicals on the surface of the aerosol droplets, and the step of orienting the aerosol onto the primed fabric where the aerosol droplet surfaces react with the layer of primer composition upon mutual contact. Representative examples of an apparatus used to generate such a plasma discharge include those provided by WO2001/59809, WO2002/28548, WO2005/110626, US2005/0178330.

Before applying the barrier composition to the layer of primer composition of the fabric, the layer of primer composition of the fabric can preferably have a high energy treatment applied thereon, such as for example, a plasma etching, plasma treatment, corona or electrostatic discharge treatment.

The process according to the present invention may comprise the step of curing the layer of primer composition and/or the from one to four layers of barrier composition; preferably individually, i.e. after each application of composition to form the corresponding layer.

In the case the layers of primer and/or the barrier composition are cured, the resulting layers will have enhanced abrasion resistance and mechanical stability.

The process according to the present invention may further comprise the step of applying an antistatic composition to the second opposite face of the fabric to form a layer of said antistatic composition on the second opposite face of the fabric.

The layer of antistatic composition comprises at least one suitable antistatic agent chosen, without limitation, from the group comprising organic phosphate esters, phosphate salts of alkaline, earth alkaline or transition metals such as for example potassium polymetaphosphate; alkenyl phosphonic acids or esters thereof; alkyl sulfonate salts; fatty acid salts; quaternary amines; sodium chloride; polyols such as polyethylene glycol; and/or combinations thereof. Preferably, the at least one antistatic agent is an organic phosphate ester.

Organic phosphate esters may be chosen among the group comprising alkyl phosphate ester such as mono- or disubstituted potassium n-propyl phosphates, mono- or disubstituted potassium i-butyl phosphates, and/or combinations thereof. Organic phosphate esters can be commercially obtained from Stepan Chemical (Northfield Ill., US) under the trademark ZELEC®.

The primer and/or barrier composition may further comprise at least one particulate material having an average particle diameter of from 0.5 micrometer to 50 micrometers or 0.5 micrometer to 15 micrometers. In the case where both the primer and barrier composition comprise at least one particulate material, it is preferable that the average particle diameter of the particulate material comprised in the primer layer is greater than the average particle diameter of the particulate material comprised in the barrier layer.

In a preferred embodiment, the primer composition comprises a particulate material having an average particle diameter that is of from 0.5 micrometer to 15 micrometers , preferably of from 2 micrometers to 10 micrometers, and the barrier composition comprises a particulate material having an average particle diameter of from 0.5 to 15 micrometers, preferably of from 0.5 to 2 micrometers.

In another preferred embodiment, the barrier composition is essentially free of particulate material, whereas the primer composition comprises a particulate material having an average particle diameter that is of from 0.5 micrometer to 50 micrometers or 0.5 micrometer to 15 micrometers, preferably of from 2 micrometers to 10 micrometers.

The particulate material may be chosen from inorganic or organic materials such as for example titanium dioxide, silica, crosslinked polymethylmethacrylate, crosslinked benzoguanamine formaldehyde resin, crosslinked benzoguanamine melamine formaldehyde resin, crosslinked siloxane, and mixtures thereof. Preferably the particulate material is crosslinked siloxane such as for example polymethylsilsesquioxane. The particulate material may be comprised in the barrier or primer compositions in amounts ranging of from 1 weight percent to 10 weight percent, more preferably of from 1 weight percent to 5 weight percent, the weight percentages being based on the total weight of the barrier or primer compositions.

The present invention also provides for a barrier fabric obtainable according to the above described process, having a first face and an second opposite face, comprising a layer of primer composition on said first face and at least one, preferably of from one to four, more preferably two or three, layers of barrier composition on the layer of primer composition, wherein the interior (as opposed to the surface) of the barrier fabric is essentially free of primer and barrier composition.

In a further embodiment, the present invention provides for a barrier fabric obtainable according to the above described process, having a first face and an second opposite face, comprising a layer of primer composition on said first face and of from one to four layers of barrier composition on the layer of primer composition, and further comprising a layer of antistatic composition on said second opposite face.

EXAMPLES

A polyethylene flash-spun fabric having a nominal basis weight of 58 grams per square meter, commercially available fromDupont under the trademark TYVEK® 1560B, was inserted into a vapor deposition apparatus and coated with different layers of composition combinations, as explained below. The web speed was of 100 meters per minute, and the compounds to be coated on the web of fabric were evaporated at 180° C. at a pressure of 1.5×10⁻² mbar. After deposition, the coating layer was cured by electron beam set to 10.3 kV and 1 A in Argon gas, at a pressure of 1.7×10⁻² mbar. The compositions are described in Table 1

TABLE 1 crosslinkable fluorinated monomeric Whitener compound, in compound, in compound, in weight percent weight percent weight percent Primer 0 100 0 composition Barrier 65 34.95 0.05 composition

The fluorinated compound was a mixture containing about 95 weight percent of perfluoroalkylethyl methacrylates, commercially available from DuPont under the trademark ZONYL® TM-N.

The crosslinkable monomeric compound was neat propoxylated neopentyl glycol diacrylate, commercially available from Sartomer Company, (Exton, US) under the trademark SARTOMER® SR9003.

The whitener compound was 2,5-thiophenediylbis(5-tert-butyl-1,3-benzoxazole), commercially available from Ciba Specialty Chemicals, (Basle, CH) under the trademark UVITEX® OB.

Since the vapor deposition apparatus could only coat the polyethylene flash-spun fabric with one layer at a time, when more than one layer was applied, the coated polyethylene flash-spun fabric was reinserted in the vapor deposition apparatus for each additional layer to be applied. The sample fabrics were then tested for repellency against hydrocarbons. The repellency rating is according to the AATCC Test Method 118(2007). The higher the repellency rating, the better the repellency against hydrophobic substances such as hydrocarbons is. Results are summarized in Table 2.

TABLE 2 First Second Third Primer barrier barrier barrier Repellency composition, layer, layer, layer, RATING in g/m² in g/m² in g/m² in g/m² (AATCC) Sample 1 0 0 0 0 0 Sample 2 0 0.6 0 0 1 Sample 3 0 0.6 0.6 0 3 Sample 4 0.6 0.6 0 0 3 Sample 5 0.6 0.6 0.6 0 5 Sample 6 0 0.4 0.4 0.4 4

As can be seen in Table 2, the repellency rating increases with the overall amount of barrier composition, such as for example between Sample 2 (1 barrier layer of 0.6 g/m², rating: 1) and Sample 3 (2 barrier layers of 0.6 g/m², rating: 3). Also, it can be seen that the repellency rating increases when the overall amount of barrier composition is present in more layers, such as for example between Sample 3 (2 barrier layers of 0.6 g/m², rating: 3) and Sample 6 (3 barrier layers of 0.4 g/m², rating: 4)). Furthermore, the presence of a primer layer influences the repellency against hydrocarbons, as can be seen when comparing Sample 2 (1 barrier layer of 0.6 g/m², rating: 1) to Sample 4 (1 primer layer of 0.6 g/m², 1 barrier layer of 0.6 g/m², rating: 3). Combining the advantages of a primer layer and of multiple barrier layers, i.e. a primer layer with multiple barrier layer yield as in Sample 5 (1 primer layer of 0.6 g/m², 2 barrier layers of 0.6 g/m², rating: 5), yields exceptional repellency ratings. 

What is claimed is:
 1. A process for manufacturing a nonwoven barrier fabric having a first face and an second opposite face, comprising the steps of: (a) applying a primer composition to the first face of the fabric to form a layer of said primer composition on the first face of the fabric, wherein the primer composition is essentially free of fluorinated compound, and (b) applying a barrier composition comprising at least one unsaturated fluorinated compound, by vapor deposition or aerosol deposition, to the layer of primer composition to form at least one layer of said barrier composition on the layer of primer composition.
 2. The process of claim 1, wherein (a) applying the primer compositionis by vapor deposition or aerosol deposition, and (b)applying the barrier composition by vapor deposition or aerosol deposition, to the layer of primer composition to form from to four layers of said barrier composition on the layer of primer composition.
 3. The process according to claim 1 or 2, wherein the at least one unsaturated fluorinated compound comprises at least one fluoro(di)acrylate monomer having the general structure of [CH₂═CRCOO(CH₂)_(x)(Su)_(y)]_(z)(C_(n)F_(2n+2−z)), wherein n is an integer ranging from 1 to 14, x is an integer independently ranging from 1 to 8, R is independently a hydrogen atom or an alkyl group with a chain length varying from 1 to 16 carbons, Su is a sulfonamide group, y is an integer independently ranging from 0 to 1, and z is an integer ranging of from 1 to
 2. 4. The process according to claim 3, wherein R is preferably a methyl or ethyl group.
 5. The process according to claim 1, wherein the barrier composition further comprises of from 10 to 50 weight percent of at least one crosslinkable monomeric compound, the weight percent being based on the total weight of the barrier composition.
 6. The process according to claim 1, wherein it further comprises the step of (c) curing the layer of primer composition and the at least one layer of barrier composition.
 7. The process according to claim 6, wherein it further comprises the step of (d) applying an antistatic composition to the second opposite face of the fabric to form a layer of said antistatic composition on the second opposite face of the fabric.
 8. The process according to claim 1, wherein the primer composition is applied to the fabric in amounts of from 0.2 to 2 grams per square meter.
 9. The process according to claim 1, wherein the amount of barrier composition per layer of barrier composition is of from 0.1 to 1 grams per square meter.
 10. The process according to claim 1, wherein the primer composition and the barrier comprise at least one particulate material having an average particle size of from 0.5 to 50 micrometers.
 11. The process according to claim 10, wherein the average particle diameter of the particulate material comprised in the primer layer is greater than the average particle diameter of the particulate material comprised in the barrier layer.
 12. The process according to claim 11, wherein the particulate material comprises crosslinked siloxane particles.
 13. A barrier fabric obtainable according to claim 1 or 2, having a first face and an second opposite face, comprising a layer of primer composition on said first face and at least one layer of barrier composition on the layer of primer composition.
 14. The barrier fabric of claim 13, having a layer of antistatic composition on the second opposite face of the fabric.
 15. 